The present invention relates to circuit card assemblies. More specifically, the present invention relates to a circuit card assembly which efficiently manages thermal energy so as to provide more optimal operation.
As is well understood, circuit boards traditionally carry multiple electronic components and related connection pathways. These components, by nature, create some thermal energy or heat during operation, which must be managed. Due to this characteristic, cooling or thermal management is yet an additional consideration when designing circuit boards. Ideally, the components are cooled in some manner while not effecting the electrical operation of the circuit(s).
Typical approaches to circuit cooling have involved heat sinks, fluid cooling systems, and cooling fans. A typical heat sink is a heat dissipating component which is often designed to maximize its surface area. This maximum surface area provides the most optimal mechanism to dissipate heat into the related atmosphere. Heat is often transmitted to the heat sink through a physical connection between the circuit board and the heat sink. As an alternative approach, liquid cooling systems provide a flow of cooling material through related components or structures which are positioned in close proximity to the electronic components. Most ideally, the electronic components are physically attached to this fluid cooling structure, so that heat dissipated from the components can easily be transferred to the fluid and carried away. Similarly, cooling fans are used in certain applications to circulate air past the electric components, thus allowing them to dissipate the heat into the immediate environment.
As is well understood, the management of heat typically requires a heat transmission path which is specifically designed to carry thermal energy away from the electrical components. Most often, this transmission path is created or generated by physical structures, which are in contact with the electrical components. Again, this is typically accomplished by having the heat sinks be physically attached to the circuit boards in some manner.
Electrical shorts and other interference is always a concern for any electrical device. As such, care must be taken to avoid shorts and undesired connections to any of the electrical components. Typically, this is avoided by utilizing non-conductive materials whenever contact is expected. Unfortunately, these non-conductive materials are typically not thermally conductive. As such, the use of these materials for heat management is not optimal.
Heat management is further complicated by the placement of electrical components. Electrical components are typically placed upon one side of the circuit board, while the back side simply contains conduction pathways and other appropriate connections. In this situation, it is fairly easy to provide a thermally conductive and electrically insulating material directly in contact with the back side of the circuit board to help carry heat away. This is made possible because electrical components do not exist on the back side, thus avoiding the possibility of shorting and other electrical problems. The thermally conductive and electrically insulating material can then be connected to a heat sink, or some other cooling structure.
In certain applications, however, the back side of the circuit board must be used to contain additional electronic components. Often these components include shunt resistors and decoupling capacitors, for example. As such, the attachment of the circuit boards directly to a heat sink, or the use of other thermal conduction materials is complicated by the existence of these back side components. Any additional structures that may be beneficial for dealing with heat also create the potential for both physical and electrical problems with the circuit board and the specific back side components. Thus, thermal management of these two-sided circuit boards is difficult and not easily accomplished.